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Materials Terminology

1. ASTM - American Society for Testing and Materials
2. SAE - Society of Automotive Engineers
3. Abrasion - The wearing away of a surface in service by mechanical action, such as rubbing, scraping or erosion.
4. Abrasion Resistance - The ability of a rubber compound to resist mechanical wear.
5. Bleeding - Migration to the surface of plasticizers, waxes or similar materials, to form a film or bead.
6. Blemish - A mark, deformity or injury which impairs appearance.
7. Blister - A raised spot in the surface, or a separation between layers, usually forming void or air-filled space in the vulcanized article.
8. Bloom - A dusty or milky looking deposit that sometimes appears on the surface of an molded product after molding and storage, caused by migration of a liquid or solid to the surface. Not to be confused with dust from external sources.
9. Brittleness - Tendency to crack when deformed.
10. Compression set - The amount by which a rubber specimen fails to return to its original shape after release of compressive load.
11. Elasticity - The property of an article which tends to return to its original shape after deformation.
12. Elongation - Also known as "ultimate elongation", or percent increase in original length of a specimen when it breaks.
13. Flame Resistance - The resistance to burning of material that will not withstand combustion under ordinary conditions.
14. Flash - Excess rubber left around a rubber part after molding, due to space between mating mold surfaces; removed by trimming.
15. Hardness - Resistance to a disturbing force. Measured by the relative resistance of a material to an indenter point of any one of a number of standard hardness testing instruments.
16. Heat Aging - A test for degradation of physical properties as a result of exposure to high temperature conditions.
17. Modulus - Tensile stress at specific elongation. (Usually 100% elongation for elastomers.)
18. Oil Swell - The change in volume of a rubber article due to absorption of oil or other fluid.
19. Ozone Resistance - Ability to withstand the deteriorating effect of ozone (which generally causes cracking.)
20. Specific Gravity - Ratio of the weight of a given substance, to the weight of an equal volume of water, at any specific temperature. Sphericity: The measure of a tolerance of a molded ball, or ground ball, in reference to a perfect sphere; also described as "roundness".
21. Temperature range - Maximum and minimum temperature limits in which a seal compound will function in a given application.
22. Thickness - available thickness range
23. Tensile range - Force, in pounds per square inch, required to cause the rupture of a specimen of rubber material.
24. Volume Swell - An increase in the physical size caused by the swelling action of a liquid. ( ie. oil )
25. Tear resistance - Resistance to growth of a cut or nick when tension is applied to the cut specimen. Commonly expressed as pounds per square inch thickness.
26. Weather resistance - The ability to withstand weathering factors, such as: oxygen, ozone, atmospheric pollutants, erosion, temperature cycling and ultraviolet radiation.

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